The following invention relates generally to the field of methods of chemical purification. More specifically, the present invention relates to a method of producing natural health or medicinal products from Cannabis species, for example, industrial hemp.
Recently, public interest in Cannabis as medicine has been growing, based in no small part on the fact that Cannabis has long been considered to have medicinal properties, ranging from treatment of cramps, migraines, convulsions, appetite stimulation and attenuation of nausea and vomiting. In fact, a report issued by the National Academy of Sciences"" Institute of Medicine indicated that the active components of Cannabis appear to be useful in treating pain, nausea, AIDS-related weight loss or xe2x80x9cwastingxe2x80x9d, muscle spasms in multiple sclerosis as well as other problems. Advocates of medical marijuana argue that it is also useful for glaucoma, Parkinson""s disease, Huntington""s disease, migraines, epilepsy and Alzheimer""s disease.
Marijuana refers to varieties of Cannabis having a high content of xcex949-tetrahydrocannabinol (xcex949-THC), which is the psychoactive ingredient of marijuana whereas industrial hemp refers to varieties of the Cannabis plant that have a low content of xcex949-THC.
The controversy regarding the medicinal use of marijuana is centered not only on what is delivered but on how it is delivered. Specifically, the primary method used to deliver marijuana into a patient""s system is by smoking the marijuana; however, smoking increases an individual""s risk for cancer, lung damage and emphysema. Furthermore, as discussed above, marijuana does contain high levels of a psychoactive drug, xcex949-THC. As such, there has been considerable debate as to whether or not the potential health benefits of smoking marijuana outweigh the health benefits.
However, it is of note that xcex949-THC is only one of a family of about 60 bi- and tri-cyclic compounds named cannabinoids. These natural products usually contain a 1,1xe2x80x2-di-methyl-pyrane ring, a variedly derivatized aromatic ring and a variedly unsaturated cyclohexyl ring, and include for example the non-psychoactive cannabinol, cannabidiol and cannabinolic acid. These latter compounds have been suggested to contribute to some of the beneficial effects of Cannabis, such as cell protection, immunosuppression and ant-inflammatory properties. This suggests that these non-psychoactive cannabinoids recognize the same cellular receptors as xcex949-THC but, due to structural differences, do not have the same side effects.
In addition, Cannabis species also contain a related class of compounds, the cannflavins. These natural products usually contain a 1,4-pyrone ring fused to a variedly derivatized aromatic ring and linked to a second variedly derivatized aromatic ring, and include for example the non-psychoactive cannflavins A and B. These compounds have been suggested to contribute some of the beneficial effects of Cannabis, such as analgesia and anti-inflammatory properties, and as such are considerably more effective than aspirin.
Clearly, a process is needed for preparing natural health products containing the non-restricted compounds present in marijuana (and also in industrial hemp) to be used for medicinal purposes.
According to a first aspect of the invention, there is provided a method of preparing a Cannabis extract comprising:
harvesting Cannabis composed of seed and chaff;
separating the chaff from the seed;
extracting the chaff with a solvent, thereby producing an extract;
passing the extract, if desired, over a chromatographic column arranged to fractionate xcex949-THC out of the extract; and
collecting the fractions lacking xcex949-THC from the column, thereby producing a whole hemp extract without the xcex949-THC.
The chaff may be green or dried and the chaff may be ground prior to extraction.
The collected fractions may be concentrated.
The Cannabis may be, for example, industrial hemp.
The solvent may be an organic solvent, selected from the group consisting of: a petroleum derived hydrocarbon, for example, toluene, trimethylpentane; a low molecular weight alcohol, for example, ethanol; a low molecular weight chlorinated hydrocarbon, for example, chloroform and dichloromethane; or a supercritical fluid such as CO2 with or without an organic solvent modifier. Extraction may also occur using a technique referred to as accelerated solvent extraction or may use subcritical water.
According to a second aspect of the invention, there is provided a hemp extract isolated according to the above-described method.
According to a third aspect of the invention, there is provided a pharmaceutical composition comprising the hemp extract according to the abovedescribed method.
According to a fourth aspect of the invention, there is provided a method of extracting a cannabinoid, cannflavin or essential oil from Cannabis comprising:
harvesting Cannabis composed of seed and chaff;
separating the chaff from the seed;
extracting the chaff with a solvent, thereby producing an extract;
passing the extract over a chromatographic column arranged to fractionate the cannabinoid, cannflavin or essential oil of interest out of the extract; and
collecting the fractions containing the cannabinoid, cannflavin or essential oil of interest from the column, producing a purified cannabinoid, cannflavin or essential oil. The cannflavins may be cannflavin A or B or other related cannflavin-type compounds.
The cannabinoid may be selected from the group consisting of: cannabidiol (CBD); cannabinol (CBN); cannabigerol (CBG); cannabichromene (CBC); cannabidivarol (CBDV); tetrahydrocannabidiol (THCBD); tetrahydrocannabigerol (THCBG); tetrahydrocannabichromene (THCBC); tetrahydrocannabidivarol (THCBDV); A8-THC; the carboxylic acid precursors of the foregoing compounds; and related naturally occurring compounds and their derivatives.
The chaff may be fresh or dried, and the chaff may be ground prior to extraction.
The collected fractions may be concentrated.
The Cannabis may be for example industrial hemp.
The solvent may be an organic solvent, selected from the group consisting of: a petroleum derived hydrocarbon, for example, toluene, trimethylpentane; a low molecular weight alcohol, for example, ethanol; a low molecular weight chlorinated hydrocarbon, for example, chloroform and dichloromethane; or a supercritical fluid such as CO2 with or without an organic solvent modifier. Extraction may also occur using a technique referred to as accelerated solvent extraction or may use subcritical water.
According to a fifth aspect of the invention, there is provided a purified cannabinoid, cannflavin, or essential oil prepared according to the above-described method.
According to a sixth aspect of the invention, there is provided a pharmaceutical composition comprising the purified cannabinoid, cannflavin or essential oil prepared according the above-described method.
The invention will now be described by way of examples, although the invention is not in any way limited to the examples described herein.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred methods and materials are now described. All publications mentioned hereunder are incorporated herein by reference.
Definitions
As used herein, xe2x80x9cindustrial hempxe2x80x9d refers to varieties of the Cannabis plant that have a low content of xcex949-tetrahydrocannabinol (xcex949-THC).
As used herein, xe2x80x9cchaffxe2x80x9d refers to the chopped plant material remaining after the seed of the hemp has been harvested and separated by the process known as threshing.
As used herein, xe2x80x9csupercritical fluidxe2x80x9d refers to materials that are under sufficient pressure and heat that they are no longer distinctly liquid or gaseous.
As used herein, xe2x80x9csubcritical waterxe2x80x9d refers to water that is heated under pressure, but is below its critical point; thus it is still a liquid.
As used herein, xe2x80x9ccannabinoidsxe2x80x9d refers to a family of natural products that usually contain a 1,1xe2x80x2-di-methyl-pyrane ring, a variedly derivatized aromatic ring and a variedly unsaturated cyclohexyl ring and their immediate chemical precursors.
As used herein, xe2x80x9ccannflavinsxe2x80x9d refers to a family of natural products that usually contain a 1,4-pyrone ring fused to a variedly derivatized aromatic ring and linked to a second variedly derivatized aromatic ring.
As used herein, xe2x80x9cessential oilsxe2x80x9d refers to a family of natural products that usually contain a multiple of the 5-membered isoprene unit variedly substituted, often cyclized to form one or more ring systems. They may also contain series of aldehydes and/or ketones and esters of a variety of carboxylic acid substituted compounds.
Described herein is a method of processing Cannabis and extracting cannabinoids, cannflavins or essential oils therefrom. In one embodiment, the extract is run over a column that fractionates xcex949-tetrahydrocannabinol out of the extract, thereby producing an eluent that is free of xcex949-THC. The eluent may then be concentrated or otherwise treated by means known in the art to produce a natural health product, that is, a whole hemp extract with the xcex949-THC removed. In some embodiments, the fractions containing xcex949-THC may be collected or pooled or the extracted xcex949-THC may be eluted. In another embodiment, the extract is run over a column arranged to fractionate a specific cannabinoid or class of cannabinoids other than xcex949-THC. In this embodiment, the fractions containing the cannabinoid, cannflavin or essential oil or class of cannflavins, cannabinoids or essential oils of interest are collected, thereby producing purified cannabinoid(s), cannflavin(s) and/or essential oil(s). Compounds isolated by this method may include but are by no means limited to, for example, cannabidiol (CBD), cannabinol (CBN), cannabigerol (CBG), cannabichromene (CBC), cannabidivarol (CBDV), tetrahydrocannabidiol (THCBD), tetrahydrocannabigerol (THCBG), tetrahydrocannabichromene (THCBC), tetrahydrocannabidivarol (THCBDV), A8-THC, the carboxylic acid precursors of the foregoing compounds, and related naturally occurring compounds and their derivatives. Compounds isolated may also include cannflavins A and B and related compounds. Compounds isolated may also include essential oils and their individual components.
The invention will now be described by way of examples; however, the invention is in no way limited to these examples.
In the example described herein, industrial hemp is harvested and the hemp seeds are threshed from the chaff. The chaff is collected and may then be dried or extracted green. In the embodiment described herein, the chaff is dried and is then finely divided, ground or pulverized. The ground chaff is then extracted with a solvent. In this embodiment, the time of residency of the ground chaff in the solvent is up to approximately 2-4 hours. Furthermore, the mixing ratio of chaff to solvent is such that the chaff can be suspended in the extracting medium during the extraction process. Specifically, in this embodiment the volume ratio is between 10:1 to 100:1. The solvent may be an organic solvent, for example, a petroleum derived hydrocarbon such as for example toluene or trimethylpentane, a low molecular weight alcohol such as for example ethanol, or a low molecular weight chlorinated hydrocarbon such as for example dichloromethane. As will be appreciated by one knowledgeable in the art, other suitable solvents known in the art or combinations thereof may also be used, and the time of residency, volumes and mixing ratios may be varied based upon the cannabinoid(s) to be extracted. In some embodiments, the extract may be concentrated by evaporation of the solvent.
In some embodiments, a supercritical fluid with or without an organic solvent modifier such as methanol may be used as an extractant. As discussed above, supercritical fluids are materials that are under sufficient pressure and heat that they are no longer distinctly liquid or gaseous; as a consequence, they have the penetrating power of gases and the solvating power of liquids. An example of a supercritical fluid is CO2, which is an accessible candidate because it can be made into a supercritical fluid above 32xc2x0 C. and 73 atmospheres. Furthermore, adjustment of the temperature and pressure can vary the effective polarity of the supercritical fluid. In addition, it is of note that the addition of small quantities of other solvents as modifiers can assist in designing the appropriate solvent for specific target analytes. Thus, the supercritical fluid can be used to extract specific compounds from hemp extract based on their chemical properties. It is of note that other suitable supercritical fluids known in the art may also be used as solvents in some embodiments. It is also of note that accelerated solvent extraction, extraction with subcritical water, or extraction with steam may also be used.
The extract is then passed through a chromatographic column, for example, an HPLC column or a reversed phase HPLC column. In one embodiment, the chromatographic column is arranged for fractioning xcex949-THC out of the eluent. That is, as the extract is passed over the column, xcex949-THC is differentially retained or detained on the column. As a result, as the extract comes off the column, the initial fractions eluted off the column will be free of xcex949-THC. These fractions free of xcex949-THC are pooled, thereby producing a whole hemp extract with xcex949-THC removed. In some embodiments, the xcex949-THC may be eluted from the column, extracted or concentrated, for purifying xcex949-THC. In alternative embodiments, the chromatographic column is arranged for fractionating a specific cannabinoid, cannflavin or essential oil or class of cannabinoids, cannflavins or essential oils out of the eluent, for example, cannabidiol (CBD), cannabinol (CBN), cannabigerol (CBG), cannabichromene (CBC), cannabidivarol (CBDV), tetrahydrocannabidiol (THCBD), tetrahydrocannabigerol (THCBG), tetrahydrocannabichromene (THCBC), tetrahydrocannabidivarol (THCBDV), A8-THC, the carboxylic acid precursors of the foregoing compounds, and related naturally occurring compounds and their derivatives. In alternate embodiments, the chromatographic column is arranged for fractionating cannflavins A and B and related naturally occurring compounds and their derivatives. In alternate embodiments, the system is arranged to fractionate the components of essential oils. It is of note that the provided list of compounds is by no means exhaustive and is in no way intended to be limiting. In these embodiments, the compound(s) of interest are retained or detained on the column so that the last fractions of the extract eluted from the column contain the compounds(s) of interest. The fractions containing the compound(s) of interest are pooled. In some embodiments, different compounds may be extracted with different solvents and then combined into a single extract. As will be appreciated by one knowledgeable in the art, in this manner, several different cannabinoids could be purified from a single extract.